(1) Field of the Invention
The present invention relates to an evaporation fuel processing device.
(2) Description of Related Art
Conventionally, in order to prevent evaporation fuel from being discharged to the atmosphere from a fuel tank and the like of a vehicle, an evaporation fuel processing device (hereinafter also referred to as a canister) which temporarily adsorbs fuel components in the evaporation fuel has been used.
As such a canister, a canister 101 as shown in FIG. 6 is known (e.g., refer to JP-A-2002-235610), which includes: a case 105 formed with a tank port 102, a purge port 103, and an atmospheric air port 104; a main chamber 106 communicating with the tank port 102 and the purge port 103, and an auxiliary chamber 107 communicating with the atmospheric air port 104, the main chamber 106 and the auxiliary chamber 107 formed in the case 105 and communicating with each other in a part on an opposite side of the atmospheric air port 104; a first adsorbent layer 111 filled with activated carbon and formed in the main chamber 106; a second adsorbent layer 112, a third adsorbent layer 113, and a fourth adsorbent layer 114 filled with the activated carbon and serially disposed in the auxiliary chamber 107; and partition plates 121 and 122 disposed between the second adsorbent layer 112 and the third adsorbent layer 113, and between the third adsorbent layer 113 and the fourth adsorbent layer 114, respectively.
In this canister 101, a volume of the fourth adsorbent layer 114 is set smaller than that of the other adsorbent layers 111, 112, and 113 so as to reduce blow-by of the evaporation fuel to the atmosphere.